None of these things ever work. If a DVD/CD is scratched enough so that data is removed the only way to bring it back is to make a new one, or buy a replacement. ThePirateBay.org - if you a cheap-@$$ and wont buy it again to replace the one you put in my history teachers vag for a week letting it get all scratched up from the gravel she has collected.
If the DVD/CD is only scratched on the protective coating, I suppose if you could polish it up well enough it would work, but scratches that don't go beyond the clear coating don't tend to render the DVD/CD to be unreadable.
